and further reduced water exchange from the growing mussel banks in the inlet led Botn to an ecological crisis with surface algal blooms and lifting of very poisonous rotten bottom water. To improve conditions the municipality of Rissa restricted the eutrophication in the drainage area and installed a bubbler facility (like in an aquarium but bigger) at a depth of to distribute more of the water exchange to deeper levels. The Great Quick Clay Slide of 1978 On 29 April 1978, a big quick clay slide eradicated several farms on the southeast corner of Botn, killing only one person. Many inhabitants fled from the scene as the edge ate its way inward from the shore. Two local teenagers made a famous 8 mm film of the cracking, sliding, and collapsing of the clay landscape. A high tsunami caused some destruction on the northern shore of Botn. See also List of lakes in Norway References Indre Fosen Lakes of Trøndelag